Researchers Try Using Body To Heal Itself

February 25, 1986|By Shari Roan, Staff writer

It sounds like science fiction: a leg muscle removed and sewn into a heart. Tissue from an adrenal gland transplanted into the brain.

But this is not science fiction. These examples represent some of the most exciting and progressive research on irreversible heart disease and brain diseases, such as Alzheimer`s and Parkinson`s disease.

The research involves a process called tissue grafting. And although two experiments described below are many years from widespread human use, tissue grafting holds much hope for future medical treatment.

IRREVERSIBLE HEART DISEASE

An estimated 100,000 Americans are diagnosed with irreversible congestive heart failure each year. About half these patients die within one year of diagnosis -- despite advances in cardiovascular drugs, heart transplantation and the artificial heart program.

An alternative is now being tested in which a patient`s own skeletal muscle is used to replace damaged areas of the heart, says Dr. Larry Stephenson, an associate professor of surgery at the University of Pennsylvania.

``Since none of these three available treatments can be expected to benefit this large number of patients with severe heart failure in the near future, we have been investigating a potential fourth therapeutic alternative: the use of a patient`s own skeletal muscle to augment cardiac performance,`` Stephenson reported last month at the American Heart Association`s 13th Science Writers Forum in Sarasota.

In the past seven years, studies with animals have shown that portions of the ventricles, or pumping chambers, of the heart can be constructed with skeletal muscle, said Stephenson. For humans, the muscles being studied for grafting in the heart are the diaphragm muscle, which we use for breathing; the latissimus dorsi, the large muscles in the back; the pectoralis, the muscles in the upper chest; and the rectus abdominus, the muscles in the rectum and abdomen.

Most patients could function fairly well without use of one of the pairs of those four muscles, says Stephenson, adding that plastic surgeons use some of these muscles for covering soft tissue defects in the body and for plastic surgery in breast augmentation.

In experiments, scientists first use electrical stimulation to strengthen muscles prior to grafting. After grafting the muscles into animal hearts, the muscle graft forms common blood vessels with the heart, says Stephenson.

The skeletal muscle grafts have many advantages. Because they are a person`s own muscle, they will not cause tissue rejection -- a problem sometimes encountered in heart transplants. Nor would there be a shortage of organ donors as there is in transplant. The cost of muscle skeletal transplant would be far less than either transplantation or an artificial heart.

No one has attempted using skeletal muscle in humans yet, says Stephenson. But studies will continue on what may be the most practical alternative yet for irreversible congestive heart failure.

DISEASES OF THE BRAIN

Another exciting example of tissue grafting is revealed in the March issue of Science `86 magazine, although this example is very different from the use of skeletal muscle in the heart.

According to the Science `86 report, physicians in Sweden have transplanted adrenal-gland tissue in the brains of four people who suffer from Parkinson`s disease. All four patients showed at least some temporary improvement after the grafting.

Human brain transplants are not yet done in the United States. But American researchers are watching closely the experiments in Sweden.

Unlike the muscle used in heart grafts, brain grafts involve the transplantation of only a limited number of cells. Parkinson`s disease is caused by a deficiency in the brain chemical called dopamine, which allows us to move. Besides the brain, dopamine is found in the adrenal glands, which sit atop the kidneys. In their experiments, the Swedish scientists extracted some of the cells in one adrenal gland and transplanted them into the brain.

Researchers theorized that if some of that adrenal tissue were transplanted into the brain it might grow into the cells and supply dopamine to the brain, relieving the symptoms of Parkinson`s. According to scientists who have performed brain tissue grafts on rats, when a part of the brain is damaged, other neurons in the brain attempt to respond to that damage by sprouting new fibers. These new fibers grow into the damaged area to take over some of the functions of the damaged area.

The scientists appear to be on target. The patients -- all desperately ill -- showed immediate improvement after the implants although all slowly deteriorated again. The study was successful enough, however, to warrant continuing studies of patients with degenerative brain diseases. Someday, the technique may even be applicable to Alzheimer`s disease.

If successful, these techniques may lead to other methods for using the body to heal itself.